Lamp bulbs used in vehicles have traditionally included bulbs with cylindrical metal threaded bases, or bayonet bases. These bulbs are used with a socket assembly that includes generally a housing with a socket, terminals internal to the housing, and circuit wires joined to the terminals that exit the housing and are connected to the rest of the vehicle's electrical system. The bases of such lamp bulbs received into the socket by threading, or with a partial turn twist. Increasingly, however, wedge base type bulbs are being used. A wedge base bulb includes a base formed of the same glass as the lamp bulb itself and having generally the shape of a rectangular prism, with opposed parallel sides. Filament contact wires are located against, or at least proximate to, the opposed base sides, and extend along the base sides essentially parallel to the central axis of the bulb itself. The filament contact wires are extensions of the internal bulb filament and are relatively thin and delicate, as compared to a metal bayonet base. The advantage of the wedge base bulb, however, is that it may be received into the housing socket by simply being pushed down in a straight path, generally along the central axis of the bulb. This is simpler than the threading action or the quarter turn necessary with other bulbs. As the wedge base bulb is so received, terminals internal to the housing make electrical contact with the filament contact wires. Consequently, it is common for at least that part of the terminal that physically engages the filament contact wires to be oriented substantially parallel to the straight line path followed by the bulb base as it is so received. Then, the terminals may wipe along the filament contact wires, pressing them against the opposed sides of the bulb base without damaging or moving them out of position.
The two basic types of socket assemblies for receiving a wedge base lamp bulb are "in-line" and "low profile" . In an in-line socket assembly, the whole of each terminal is essentially straight, and the circuit wires are colinear with the terminals. Therefore, the terminals and circuit wires together may be simply placed inside the housing through terminal passages formed in the housing that extend substantially parallel to the bulb axis, that is, parallel to the straight path followed by the bulb base as it is received. Such a terminal passage need not be much wider than the terminal that it receives, and will be relatively easy to seal. A good example of a typical in-line socket assembly may be seen in the U.S. Pat. No. 3,950,061 to Kausen. There, a straight terminal 76 and its colinear circuit wire 74 are received in a relatively narrow cylindrical passage 72 in housing 42, a passage that is parallel to the central axis of the bulb 10. The drawback of an in-line assembly is that it inevitably occupies a large amount of axial space, as measured along the axis of the bulb.
In a low profile socket assembly, the circuit wire is made to exit the housing perpendicularly to the axis of the bulb, thus saving axial space. One way to create this low profile is to separately attach the circuit wire to the terminal, after the terminal is already inside the housing. An example of this type of low profile assembly may be seen in the U.S. Pat. No. 3,676,834 to Kaldor et al. However, this kind of plug in circuit wire connection is inherently not as sound as when the circuit wire is solidly crimped to the terminal first. But, if a terminal and ninety degree circuit wire are to be placed together, as a unit, through a passage into a housing, in the same fashion as in an in-line socket assembly, then the terminal passage will have to be as wide as the length of the terminal. This would require a very large passage opening, which would be very difficult to seal, as well as potentially weakening the housing. One obvious solution to this problem is to simply integrally mold the terminal and ninety degree circuit wire together into the housing, but this is clearly not preferred, because of servicability problems. Other known solutions include making the terminal in two parts, one part internal to the housing and oriented parallel to the bulb axis, and another part perpendicular to the first part. The second part of the terminal is separately received into the housing through a relatively narrow passage to connect it to the first part. An example of this type of low profile assembly may be seen in the U.S. Pat. No. 4,418,973 to Smetan et al. Clearly, a two part terminal is less desirable that a unitary terminal. One distinctive solution to the problem may be found in the U.S. Pat. No. 4,101,187 to Collier, which discloses a hollow, L shaped plastic housing molded so as to open like a book, with a living hinge. An L shaped terminal and attached ninety degree circuit wire may be placed inside, and the housing closed. Besides being difficult to mold, such a housing is undesirable because of the large perimeter seam that it would leave, which would be difficult to seal.